Is the government’s overly aggressive solar thrust in public interest?
(This piece appeared in the Feb 11th issue of EPW ; reproduced below)
Shortly after coming to power the Modi government declared a fivefold increase in the 2022 target for solar generation capacity in the country to an eye popping 100 GW. Less than a year earlier, India’s electricity establishment had estimated 100GW to be India’s solar potential till 2032 (MoP 2014:22)! To see the numbers in perspective, India’s current solar capacity is less than 8 GW.
The target has been set without reference to the coal-fired capacity addition in progress and at a time when capacity utilization of existing thermal plants is very low and there is a large uncertainty on how electricity demand will develop in the next few years (Singh 2016, Tongia 2016:6).
The only argument the government has offered in favour of its aggressive solar thrust is that this would help India meet its international commitments on carbon emissions (GOI, 2015a). There have been questions raised about whether such a rapid build-up of non-fossil fuel capacity is indeed necessary to meet these commitments (Tongia 2016:17). These have remained unanswered.
The government estimates the investment requirement for 100 GW of solar generation to be of the order of Rs 6 lakh crores. Globally, RE is a favourite of investors and the government’s solar program has been enthusiastically received. Foreign investors such as SunEdison, SkyPower, Fortum India and SoftBank and Indian business houses including Adani, Tata and Mahindra have aggressively participated in the large solar tenders. Competition is fierce and the Ministry of New and Renewable Energy has had to hire large halls to accommodate all interested players during pre-bid meetings (Kenning 2015)!
How will such an aggressive solar program impact India’s electricity distribution companies? How will it affect the cost, availability and quality of electricity for consumers? Is the pace of solar adoption pushed by the government in public interest? These are some questions that this paper attempts to answer.
1. Challenges of renewable energy on the grid
The thrust of the government is entirely on grid connected solar energy. A little background is useful to understand the challenge this poses for electricity distribution.
Electricity demand typically varies round the clock. For example, the all India average pattern shows a higher demand during the day than at night with a sharp late evening peak (PGCIL 2012: 57). It is a basic requirement of a stable electricity grid that demand and supply be “balanced”, or in other words, matched at all times and over different time scales.
Balancing demand and supply
There are several options for balancing. On the supply side, the output of power plants can be controlled to follow demand. On the demand side, the options can be to store energy when there is excess supply and to curtail demand forcibly or through economic disincentives when there is a deficit.
Conventional power plants – such as coal, gas-fired and reservoir based hydro power - are amenable to output control to varying extents. Their use in balancing is determined by their operational “flexibility” - the range over which their output can be changed and the rate at which the change can be made. The capacity available for flexible use is termed “balancing capacity”.
The output of gas-fired and hydro power plants with reservoirs can be changed rapidly and over a large range to handle changing load. These plants are high in flexibility. The old (“subcritical”) coal-fired plants were designed to provide a steady output. Output changes in these plants happen relatively slowly and over a smaller range and frequent output changes can lead to wear and tear with attendant costs. These plants are low on flexibility. Newer “supercritical” coal-fired plants are by design more flexible and resilient than the older subcritical plants (PGCIL 2012: 120-124).
Currently, demand is typically assessed from load profiles from the past (previous day, same day previous week or year) which can give an indication of the load variations to be expected. Conventional generators are scheduled to match the expected load.
The intra-day variation in demand is addressed mainly by varying output of reservoir based hydro plants. Coal plants provide the “base load” and their output is varied only in a small range (PGCIL 2012:125). In recent years, this range has been expanding steadily indicating need for increasing balancing capacity (MoP 2016b: 28). The use of gas-fired plants in balancing has been discouraged by non-availability of gas and high price.
When there is insufficient supply, “load shedding” is resorted to. The Indian grid has hardly any storage capacity available as the need for storage solutions has not been acutely felt in the past.
Implications of renewable energy for balancing
The presence of solar energy generators on the grid makes balancing more challenging for several reasons. One is that electricity regulation in India incentivizes solar energy by conferring a “must run” status on solar generators; their entire output must be accepted into the grid. This makes solar power plants “inflexible” from a balancing standpoint.
A second is that solar power is variable. Solar power plants produce power only in daylight hours and their output varies with the movement of the sun, peaking at midday. Balancing now needs to be carried out for load as well as supply variability.
A third reason is that solar output is dependent on weather. Cloudy or foggy conditions lower output and introduce intermittency into the variations. The expected output under such conditions, obtained from models using weather forecasting data, has to be available sufficiently in advance to enable scheduling of conventional generators for balancing. Since weather is not entirely predictable, actual generation will show deviations from forecasts and these have to be handled in real time.
Wind mills are the other major source of renewable energy (RE) in the Indian context. Together with solar, they account for over 90% (160 GW) of the RE target for 2022. These plants also have a “must run” status and produce output that is variable and influenced by weather conditions. From a balancing perspective, they have issues similar to solar.
Balancing areas in India’s federal electricity setup
There is another dimension to balancing that derives from India’s federal electricity setup - electricity provisioning is a state government responsibility. Each state has to maintain the supply-demand balance in its own grid which becomes the “balancing area”. Access to balancing capacity commensurate with the RE capacity planned is required in each balancing area, that is, at the level of every state.
The RE potential of a state depends on various factors like the level of solar irradiation and wind conditions. Seven states – Tamil Nadu, Karnataka, Andhra Pradesh, Maharashtra, Gujarat, Madhya Pradesh and Rajasthan – are suitable for both wind and solar generation and account for 70% of the aggregate wind and solar capacity planned across India (MNRE 2016). These have been termed “RE rich” states.
As to generation, historically, states have had their own dedicated power plants or shares in the capacity of central public sector power plants. State distribution utilities procure a bulk of their power requirements (89% in 2011-12) through long term power purchase agreements (PPA’s) with these state owned plants and some private plants (NTPC 2012). The remaining comes from generators with ‘untied’ capacity that are either recently commissioned private plants that have not found long term customers or private plants operating as merchant producers.
Long term PPA’s pretty much fix the generation resources and balancing capacity in the portfolio of a state. They also come in the way of states pooling their balancing resources. A state looking for additional balancing capacity outside of its fixed portfolio has to find it from the limited pool of ‘untied’ generators.
For these reasons, there can be a wide mismatch between the balancing capacity in different states and the RE capacity planned for them.
The experience of Tamil Nadu:
Tamil Nadu currently has the highest RE capacity penetration among all states with RE (largely from wind mills) accounting for 56% of its overall generation capacity. Its balancing capacity is inadequate for this level of penetration (GIZ 2015: 54, 63-65). Use of its limited reservoir-based hydro capacity for balancing is restricted by irrigation release schedules and periods of high inflows into reservoirs when hydro power generation cannot be curtailed. Neighbouring Karnataka and Telangana, which are part of the Southern Electricity Region, are rich in hydro power resources, but these are not available to Tamil Nadu. The state has no flexible gas-fired plants and limited flexibility available in its old coal-fired plants (CEA 2013:13).
Till early 2016, in the absence of capability for wind power forecasting, short term power purchases were planned after making assumptions about wind generation. If wind power generation was greater than expected, after exhausting its limited balancing options, the state utility would have only two options - either back down power from private coal plants contracted for short term power or cut off wind power plants from the grid.
Either option has been problematic for the utility - violating contract provisions in one case and not respecting the “must-run” status accorded to wind generators in the other. The dispute involving the state utility, coal-fired plants and the wind power producers is now in the courts (Vaitheeswaran 2015). Legal issues aside, there are negative economic consequences either way. Varying power from coal plants means underutilization of capacity and higher costs related to wear and tear. Backing down wind power means wasted energy.
2. Preparations for RE
The central government’s massive RE targets require a commensurate increase in balancing capability at least in the RE rich states. Balancing resources can be augmented by dedicated transmission corridors distributing RE across states, grid storage and additional flexible generation – all long gestation infrastructure (PGCIL 2012:116). Besides resources, accurate forecasting of RE generation is essential for balancing. What follows is an assessment of the central government’s preparatory work in each of these areas.
Pumped storage is not only the most widely deployed grid level energy storage technology, it also the most flexible and competitive one (GIZ 2015: 80). Pumped storage hydro electric plants store and generate electricity by moving water between reservoirs at two different heights. While India has a very limited capacity of operational pumped storage, the electricity establishment has identified a number of hydropower projects that can be developed to support pumped storage (CEA 2013: 39-43). The government however has just woken up to the need to identify concrete projects and there is talk of setting up 10GW of pumped storage (ET Bureau 2016).
Grid level battery storage technologies are evolving and in one estimate 3-8 times more expensive than pumped storage (GIZ 2015:80). There are several vested interests active in promoting these technologies including the US – India business council and the government seems to have fallen for the hype created around them. The public sector Solar Energy Corporation of India has put out tenders for solar capacity with storage components potentially driving up the cost of solar electricity (Clover 2016). The storage component is miniscule as of now and nowhere near the scale needed to be practically useful to the distribution companies (DISCOMS).
It seems that storage can be safely discounted as an option for balancing in the run up to 2022.
Forecasting and Dispersing RE
Renewable energy management centres (REMC’s) are to be set up in at least all the RE rich states with the responsibility for state wide forecasting of RE. The costs incurred in managing the uncertainty in predicting renewable generation will not be part of its purchase cost; these costs are to be “socialized” among grid users (CERC 2015). Till mid 2015, there was no centralized forecasting for renewable generation anywhere in India (GIZ 2015:60). Tamil Nadu has inaugurated its REMC recently (Srikanth 2016).
Transmission corridors (termed “Green Energy Corridors”) providing RE clusters in RE rich states access to neighbouring states were a part of the 12th plan. The corridors are under implementation with an enlarged scope to include connectivity to the "ultra mega solar parks" and will enable RE generators to disperse electricity in a wider geography with more balancing resources than available in the RE rich states (MoP 2016b:42).
Both the forecasting and transmission infrastructure are early work in progress and there is no visibility into when they will be ready.
There is little chance of capacity addition in gas-fired thermal plants in the 2022 time frame with existing gas-fired plants running at partial capacity because of the cost of gas which has to be imported. Hydro power projects totalling over 12 GW are under construction (CEA 2015). Possibly less than half of this capacity will be amenable to flexible use. Most projects are many years behind schedule because of environmental related standoffs and opposition from local populations.
Old coal-fired plants can be made more flexible through retro-fitting. This will require capital expenditure and there are no signs that governments (who own most of these plants) are seriously considering this option. A total of 73 GW of coal capacity is under construction of which supercritical plants account for 50 GW (CEA 2016, MoEFCC 2015:72).
One can conclude that coal-fired plants, in particular super-critical ones, will be the mainstay of RE balancing. With conventional capacity addition far lower than planned RE capacity addition (of 130 GW), India’s overall “balancing potential” – the ratio of balancing capacity to RE capacity – is set to decrease in the run up to 2022.
Market for balancing capacity
The mere existence of flexibility in generation will not translate to flexible operations as the later has negative financial implications for the operator. For instance, in the case of coal-fired plants, these are due to wear and tear reducing the life of the plant, higher maintenance costs and costs associated with capacity underutilization and lower efficiency. The government is therefore moving to incentivize flexible operations. There is already a regulation to compensate generators for holding capacity in reserve for responding to grid management requests in real time. A framework for market based pricing for balancing capacity is just down the line.
Will market based incentives solve the problem of making adequate balancing capacity available in the RE rich states?
There are some constraints. Firstly, the generation capacity available in the electricity market untied to PPA’s is currently limited, though it is slated to rise with the commissioning of new plants. Secondly, inter-regional transmission constraints can come in the way of RE rich states using flexible capacity from regions other than their own.
The later problem is illustrated by the Southern Electricity Region which has been facing a generation capacity deficit for several years. Coal-fired generators in the Western Electricity region are unable to provide power to the Southern Region because of transmission bottlenecks and their capacity lies underutilized. Market based pricing for electricity has not solved the problem of electricity deficit in the southern region in five years; electricity prices at the Indian Electricity Exchange have remained significantly higher for the southern region compared to the western region from 2011 onwards (Kasturi 2016:24).
Two years after announcing massive RE targets, the government still does not have an assessment of the actual balancing capacity available with the RE rich states or how this will grow in future! It appears to believe that the market for balancing capacity will somehow solve all problems.
3. The real cost of solar
State utilities are generally strained financially and will not be keen to purchase RE as long as it is relatively expensive. To make RE more attractive, the central government has worked out ways of subsidizing it at the cost of public sector companies in the power or fuel sector. Inter-state transmission charges for solar electricity have been waived at the cost of the PGCIL.
NTPC contracts for solar power from producers and sells it to DISCOMS after subsidizing it in the following way. It “bundles” solar power with low cost power from its coal-fired plants and offers utilities power at a rate which is lower than its purchase price for solar electricity (Upadhyay 2015). This bundled price has to approach “grid parity” – the average price of electricity contracted by utilities - for NTPC to be able to find willing buyers.
Of course, even if solar prices reach grid parity it does not mean that solar has become cost effective compared to other sources of energy. The cost of balancing variability in generation through flexible capacity held in reserve must also be attributed to solar power. To this must also be added the cost of infrastructure for forecasting RE and the costs arising from errors in forecasting. The government has not even hazarded a guess at these costs yet.
As subsidies alone are not enough to make solar power attractive, the government has also taken recourse to coercion. The new tariff policy calls for high RE purchase obligations for DISCOMS with the target for solar alone being 8% of non-hydro power consumed by every utility by 2022 (MoP 2016a). To make sure that states comply with the RPO targets, such compliance has been made part of the conditions associated with the ‘Ujwal Discom Assurance Yojana’ (UDAY) that provides relief to indebted state DISCOMS (GOI, 2015b).
Negative consequences of force feeding RE
Forcing DISCOMS to absorb RE beyond their ability to handle it will have consequences for the health of the DISCOMS and the cost and quality of electricity supply. A key assumption behind UDAY is that power costs will come down with lower cost of coal and help DISCOM finances. Rapid solar penetration will push up the cost of power.
Utilities are already hard put to handle load variation even today. They lack accurate load forecasting, flexibility in conventional generation, balancing resources such as pumped storage and generation reserves to handle different eventualities on the grid (MoP 2016b: 11). For customers, this has meant a regime of poor quality and unscheduled power cuts. With high RE penetration and an expected further deterioration in balancing potential, this regime is bound to continue in to the future. The government is also preparing to use demand curtailment curtail for balancing by pushing for large scale installation of smart meters that will allow setting time-of-day tariff (MoP, 2016a).
Public interest will be better served if the pace of solar (and wind) capacity build up is compatible with the balancing capacity available with the states and their ability to manage RE variability. The government must pay as much attention to capacity building in inter-regional transmission, pumped storage and highly flexible generation as it is doing to solar generation.
Renewable energy targets based on these considerations rather than impetuous declarations will be sustainable and allow steady decrease of carbon emissions. A slower adoption of solar generation will be beneficial for yet another reason - solar power, as long term trends suggest, will only get cheaper with time.
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