Last week’s Independent Options Appraisal (IOA), which detailed the possible scenarios for carrying out a major restoration and renewal programme for the Palace of Westminster, includes a recommendation to investigate the use of “novel technologies” to reduce energy use and CO2 emissions at the building.
Among the novel technologies to be considered is a “large” solar array that could cover 190 sq m of the listed building’s roof, although the authors acknowledged that there could be resistance to the idea.
The report recommends further investigation saying: “Photovoltaic panels (PV) should also be investigated further as PV is a simple technology to install and operate, although the large PV array option may not be deliverable due to the likely visual impacts.”
But MPs could also be beneficiaries of an even more innovative technology: public sewer heat recovery system. According to the report, this has the potential to deliver the largest additional CO2 savings of 250 tonnes per year.
Described as a “new technology with little UK experience”, a public sewer heat recovery system would harvest heat given off by waste water in sewers to generate electricity. This would be achieved by retrofitting heat exchangers inside culverts or pumping sewage through heat exchangers.
Further investigation is also recommended into a cast iron roof solar thermal collector, river heat rejection, borehole direct cooling and hydrokinetic (tidal) power.
But there was no endorsement for kinetic speed bumps and kinetic energy-collecting tiles, such as the Pavegen product recently installed at Canary Wharf, with the report dismissing them due to “poor cost effectiveness”.
Although these “novel technologies” warrant further investigation they will offer a relatively small additional CO2 saving in the short term, according to the report, and these savings will diminish over time as the grid decarbonises.
However, in the long term, they will continue to offer small energy and operational cost savings and therefore should be investigated.
The report also reveals that a disappointing collection of Display Energy Certificates for the Palace of Westminster and other buildings in the parliamentary estate.
Although the report acknowledges that “the unique nature of the PoW [Palace of Westminster] makes any meaningful benchmarking very difficult” it has a DEC rating of 114 compared with a “typical building”, which would achieve 100. However, it is the second best in the parliamentary estate (see graph below).
As part of the report prepared by international consultancy Aecom, financial group Deloitte and architect HOK, M&E engineer Chapman Bathurst modelled several building services packages for Parliament.
It calculated the mechanical and electrical strategies based on Department of Energy and Climate Change (DECC) projections that CO2 emissions for grid electricity will fall by 90% by 2050, as the UK moves to greater renewable and nuclear generation.
If reductions to carbon created by grid are obtained then high efficiency heat pumps, utilising this low carbon grid electricity, will offer the greatest CO2 savings.
However, the report casts doubt on the rate of grid decarbonisation predicted by the DECC saying: “There remains significant uncertainty as to whether the electricity grid will decarbonise at the rate DECC predicts. Based on recent performance, we consider this very unlikely and the DECC projections very optimistic.”
Given this significant uncertainty the report recommends a flexible approach and the further investigation of the “novel technologies” to reduce energy use and CO2 emissions.
