Alternatives That Mitigate the Damage

In one line

Mitigation is not the same as substitution, and MU asks for the first: what to do about the damage the existing system does while it is still doing it.

Read the question correctly

Three of MU's printed papers ask for alternatives to mitigate environmental degradation, one of them adding the words caused in generating energies.

That is not a question about switching to solar. A candidate who answers it by describing renewable energy has answered the previous chapter's question again. The question is about the damage the conventional system causes now, and about the measures, technical and legal, that reduce it without waiting for the system to be replaced.

Group the answer in four families: what happens inside the boiler, what happens at the stack, what happens to the residue, and what happens on the demand side.

Family one: burn less for the same output

Higher steam conditions. A boiler operated at higher pressure and temperature converts more of its heat into work, so the same output needs less coal. Sub-critical, super-critical and ultra super-critical are the successive steps. Less coal means less of everything: less mining, less haulage, less ash, less of every pollutant and less carbon, without any additional control equipment. It is the cheapest mitigation there is, because it removes the cause rather than treating the symptom.

Better coal. Washing coal at or near the mine removes ash and stone before the railway carries them, cutting transport energy and the ash load at the station.

Cogeneration, and waste heat recovery. Section 2(12) of the Electricity Act defines cogeneration as a process which simultaneously produces two or more forms of useful energy, including electricity, and section 61(h) requires the tariff regulator to be guided by the promotion of co-generation. A sugar mill burning bagasse, a refinery using process heat, a steel plant using blast furnace gas: each takes two useful outputs from one unit of fuel.

Retiring and refurbishing. Old, small, inefficient units burn more coal per unit than new large ones. Retirement is mitigation, and so is the refurbishment of what is kept.

The legal instrument for this whole family is section 14 of the Energy Conservation Act. Clause (a) lets the Central Government specify norms for processes and energy consumption standards for an industrial unit or establishment which consumes, generates, transmits or supplies energy; clause (b) specifies the unit; and clause (c) can require a non-conforming industrial unit to close its operations. A generating station is regulable for efficiency under the conservation statute even though the Electricity Act delicensed it.

Family two: clean what leaves the stack

Particulate control. Electrostatic precipitators and bag filters capture fly ash before it leaves the chimney. This is the oldest and best established control, and it is a standard condition of consent.