The headline figures: somewhere between 822 - 2,281 tcf (trillion cubic feet) of shale gas, with 1,300 tcf being the best estimate.
This map shows the area covered by the report:
In case you are wondering what the green and red dots are on the map above, these represent existing oil and/or gas wells in the region. So onshore drilling isn't new to the area. The two maps below show the seismic lines and well logs used to create the report. You can see that there is a lot of data available - much of the wells and seismic will be legacy data from past exploration for the conventional fields shown above.
If you are a bit of a geo-geek, I really recommend you check out the UK Onshore Geophysical Library, where you can actually see all the wells and seismic data for yourself. They have a slick little interactive map viewer where you can plot all sorts of information.
So, what does 1,300tcf mean for the UK? The key thing to think about is recovery factors - how much of the gas can we actually get out of the ground. It has become conventional to assume a recovery factor of 10%. I'm not sure why, when US experience points to more like 20-30%, but lets be conservative and stick to 10%.
10% of 1,300tcf is 130tcf of produceable gas. Keep in mind that the UK's annual consumption is 2-3tcf. So 130 divided by 2.5 is 52 years of total UK gas consumption.
A different and perhaps more illuminating comparison is with the largest conventional gas fields in the world, which you can see here. 130 tcf of recoverable resource would place the Bowland shale as the 4th largest field in the world, behind only the Qatari Pars Dome and Russia's two largest fields.
If money, rather than volumes, is of more interest to you then consider: 130tcf is approximately 130 billion MMBTU. The current European gas price is something like $8 per MMBTU, so the total value of recoverable gas in the Bowland shale is something like 130 billion x $8 = $1,000,000,000,000, or $1 trillion dollars (cue much of this). Of course, that money will be shared out amongst the companies involved (and the many UK workers they will employ) and the UK government, which will take its cut via the taxman. It remains to be seen exactly how the government tax the shale gas industry - I hope they set up something similar to the Norwegian Sovereign Wealth Fund.
Of more immediate interest is the decision by the government to ensure that, as well as the taxman, local communities benefit from shale gas development. For every well pad, £100,000 will go to local communities, plus 1% of production revenues.
Let's examine those figures in more detail. A typical well pad might have 10 lateral wells diverging from a single pad. A typical total recovered volume for a single well in US is 3 bcf (billion cubic feet) per well (estimate from the recent IoD shale gas report). So a single wellpad might produce 30 bcf, or 30 million MMBTU, which at $8 per MMBTU is $240 million (or about £156 million). 1% of £156 million is £1.5 million. Add in the additional £100,000 fee and we're up to £1.6 million going to the local community, for a site covering a couple of hectares and looking something like this:
How does this compare in terms of electricity generation? 30 bcf of gas will generate 5,000 GWh of electricity. If a single well pad is operational for 30 years, that's an average of 166 GWh per year (in reality, more will be produced in the earlier years, with a decline through time). This compares with the average output of 150GWh that we get from from the UK's largest onshore wind farm, Scout Moor:
Perhaps the UK government can spend some of its $1 trillion windfall on research on improving renewables, nuclear fission, or finally working out how to get fusion working...