Battery benefits questioned | Letter

Scottish Power claims it is making a 'significant step' forward with renewable energy, but David Miller has doubtsJillian Ambrose (Report, 11 June) claims that a 50MW battery system is a "significant step". But how significant a step does not depend upon the instantaneous energy output in megawatts. Most significantly, it depends on how long it can keep this energy flow going. So the relevant measurement, to compare with rival systems, would be in MW hours (which are what we pay for in our electricity bills).David Miller(Emeritus professor of physics and astronomy at UCL), Londono Join the debate - email guardian.letters@theguardian.com Continue reading...