Tuesday, June 2, 2015

MUSINGS FROM PRIYADARSHINI KARVE: Nuclear Vs Renewable... Contd

In last week's MUSING, I tried to address a commonly expressed opinion: How can we possibly meet our exponentially growing requirement of energy, just through renewable energy sources? We have no option but to focus on nuclear power. My take on this is mostly from a sustainability perspective. In case you missed this post, here is the link:



Last week, I pointed out that we don't really need everything to be run on electricity, and that generation of electricity cannot possibly be the only focus if our goal is to achieve energy security. But let me keep that point aside. Let's for the sake of argument assume that we want to focus only on electricity generation. From that perspective, today, let me address the issue of why renewable energy is considered to be inadequate to meet our growing energy requirement, and the fallacies in that particular outlook.

As per the data available from the Ministry of New and Renewable Energy (MNRE), as on 31 March 2013, the total installed power generation capacity within India was 223 GW. Out of this, only 2.1% came from nuclear power plants. On the other hand, 17.7% electricity came from hydropower, which too is a form of renewable energy, although it has a number of negative impacts. The contribution of renewable energy (the energy source is either inexhaustible or recoverable, AND there are relatively less or no environmental and social impacts) to the power generation was 12.3%. This did not include waste to power type of projects, which also can come under renewable, but are a bit controversial and anyway not contributing much at this point in time. The rest of the capacity was based on non-renewable fossil resources. So, obviously, already renewable energy seems to be playing a much bigger role in our electricity generation, compared to nuclear power. 

There are four major renewable energy sources that have been focused on for electricity generation in India. These are: wind, small hydro, Biomass (including co-generation using bagasse), and solar power. None of these resources have been used anywhere close to their 100% potential as on date. Again, to quote MNRE data, on 31 March 2013, 19% of the wind potential had been used, 20% of small hydro, 17% of biomass and less than 0.5% of solar was utilised. 

So what is stopping the expansion of renewable energy sector? The limiting factor is land area. It is typically believed that because renewable energy sources are scattered (e.g., biomass), or intermittent (e.g., wind), or dilute (e.g., solar), the land area involved per MW power generation capacity is much more for a renewable-based unit compared to a coal fired power plant. 

I think this logic is faulty on two counts. 

Firstly, to make a fair comparison we need to include the area of the coal mine(s) contributing the coal to a power plant, and the land occupied by the mountain of ash generated by the power plant when we calculate the land area involved per MW power generation capacity. 

Secondly, we are assuming that the existing mode of power generation and distribution is the only option available. The system of generating a few hundred MW to a few GW of power at one location and then using a grid of wires to distribute it to places where electricity is required is a system that has worked well for coal fired power plants. However, when the same concept was used for hydroelectricity, it required construction of  large dams, which brought its own social and environmental issues, such as displacement of people, submergence of fertile land or ecologically valuable resources, impact on downstream water availability, etc. On the other hand, micro-hydel systems, which make use of small perennial water flows to generate small amount (typically a few hundred kW) of power for use in the vicinity of the system serve a local need at zero or very little social and environmental cost.  

Why are we then not transferring this lesson to power generation using other renewable energy sources? Is it really necessary to put up huge wind or solar energy farms? Wind and solar energy or waste/surplus biomass are available everywhere but in varying and small quantities. This is not necessarily a disadvantage. It actually allows us to design systems that match a local need with local availability of the resources, by combining two or more resources. Furthermore, renewable energy works the best when it is tailored for delivery of a specific service. Traditional water or wind mills, biomass fired boilers, etc., and modern solar lights, solar water heaters, etc., are excellent examples of this. 

Decentralisation has the additional advantage of more equitable energy access. Today, even if the grid covers more than 90% of the country, it does not mean that 90% of the population has 24/7 access to energy. How much power to flow through the wires going to a particular location is centrally governed, and the urban areas always get more electricity supply than the rural areas. This situation will not necessarily change simply by replacing coal fired power plants with nuclear power plants, or even by large wind or solar farms. On the other hand, if we focus on renewables and really want to make them work at high resource and energy efficiency, there is no option but to decentralise - wherein every city, town, village, factory, institution, etc., can have a power plant tailored to meet its requirement, independent of each other. Demand side energy management will have to be practiced to make the most of the power available from the local resources, which will keep us focused on our 'needs' and make the 'greed' based consumption appropriately costly. Having a large number of small and low tech power plants can also be a huge employment generator. 

With that I rest my case. Do you still believe in the inevitability of nuclear power for our development?

Note: The power generation related statistics in this write up is from the source: 

Priyadarshini Karve
Director





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