SOLAR MASTERPLANNING RTPI CONFERENCE / 10th JULY, 2015 PLANNING FOR SUSTAINABLE ENERGY AND CONSTRUCTION

• Background - an approach to a solar master-planning policy for Plymouth ‘to optimise for’ (first in UK).

• Partnership Plymouth City Council, LightUp Analytics, University of Plymouth and in consultation with BRE.

• Jon Selman, Plymouth City Council. Gary Jackson, LightUp Analytics.

Introduction

• Aims: To develop a robust solar masterplanning policy for Plymouth in the Plymouth Plan that optimises development for energy efficiency.

• Plymouth Plan is currently in draft form.

Policy Aims

• National Planning Policy Framework (DCLG March 2012) Paragraph 96 Local Authorities should expect new development to take account of landform, layout, building orientation, massing and landscaping to minimise energy consumption.

• Planning Portal clarifies that Paragraph 96 can be achieved via “Passive Solar Design”, defined ‘as the siting and design of buildings to maximise the use of the sun’s energy for heating and cooling’. It suggests the potential benefits can only be realised by careful siting and layout.

• Whilst fabric measures will be addressed through Building Reg’s, only planning can influence the layouts of developments.

Why is this relevant to Planning?

• Easier to achieve greater energy efficiency in the Construction Phase.

• Renewable energy potential.

• Reducing carbon emissions.

• Daylight access.

• Amenity & Well-being.

What are the Benefits?

Can we design with natural light?

Previous Standards •

1920 1997

Current Standards

1991 2011

• Planning Policies need a robust evidence base

• Solar Optimisation Report

(http://www.plymouth.gov.uk/ solar_optimisation_report.pdf )

Three theoretical case studies to demonstrate benefits and implications.

Developing a robust evidence-base

Findings

Case Study

Reality

0%10%20%30%40%50%60%70%80%90%

All

Proj

ect 1

Proj

ect 2

Proj

ect 3

Proj

ect 4

Proj

ect 5

Proj

ect 6

Proj

ect 7

Proj

ect 8

% pass Average Daylight Factor (BS8206-2)

Student led research project results from 896 homes Supported with funding from ICCI

• The Co-Heating Test works by “heating the interior of a building to a uniform temperature and then recording the amount of electrical energy needed to retain this temperature over a period of around two to three weeks.”

• It takes into account solar irradiation and wind; as it then excludes them!

• In an NHBC study, the results varied by more than 28% (-17% < SAP < +23%) The study found that solar gain was the single largest cause of the difference. (NHBC, NF54)

Heating Demand

Germany (1998) Energy Reduction Measure Savings (Heating Demand)

Solar Gain (distance between buildings)

Up to 8%

Solar Gain (Orientation) Up to 7%

Avoid Wind Chill / Wind breaks Up to 1%

Building Arrangement Up to 15%

Build Shape Up to 50%

Building Geometry Up to 14%

Conservatories / Sunspaces Up to 2%

Roof / Active Solar Up to 50%

Green Roof Facades Up to 0.5%

Zoning Plan Up to 1%

(Munke & Zehner 1998)

VSC (Vertical Sky Component)

Moving beyond Rules of Thumb

31% 28%

BS8206-2

15%

θ1

θ2

Shading

77.8%

“ Percentage of the usable amenity space that receives more than 2 hours sunshine on 21st March. ”

Probable Sunlight Hours

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

61.9 85.5 123.3 187.5 224.8 222.8 213.8 204.4 160.8 115.5 75.3 54.5

Plymouth Average Monthly Sunshine Duration (hrs) [Source: Met Office] (30 year average Climate data)

“ The long-term average of the total number of hours during the year in which direct sunlight reaches the unobstructed ground (when clouds have been taken into account ”

Probable Sunlight Hours

ANNUAL

> 25%

WINTER

> 5%

Screening Parameters

VSC

WPSH

27% 27%

11% 25%

Design Implications

33.9% VSC > 15-27% VSC 28% WPSH > 5-10% WPSH

21m

GIR 27

2 Storeys 30deg Roof

25° / 27%

45° / 15%

65° / 5%

Practicality

Matthew Clark, M Arch Student 2014

Fabric First, What Next?

(Plymouth University, 2014)

• Delivering NPPF / Delivering Sustainable Sites.

• Clear Town Planning responsibilities; we are not ‘building technologists’.

• Daylight – reduced Lighting/Electricity Demand.

• Winter sunshine is generally greater to the South – reduced Energy/Carbon Demand.

• Sunlight Analysis should be climate-derived.

Policy Drivers

Draft Policy Draft Plymouth Plan Policy

The LPA will promote development that reflects the risks posed by climate change and the need for society to move towards a low carbon future, by:

7. Expecting development to:

1). Optimise solar gain and solar access in the layout of development aiming to achieve a minimum of 10 per cent Winter Probable Sunlight Hours (WPSH), and a minimum Vertical Sky Component (VSC) of 27 per cent to Living Rooms, Kitchen, Bedrooms and non-residential rooms having reasonable expectation of daylight.

Next Stages • Is the current draft policy wording right?

Peer review by BRE, etc

• Further case studies- testing approach in practice- how easy is it to apply and understand benefits?

• Taking the policy through examination

• SPD Guidance- are developers and consultants clear about implications and application? Being clear about risk of overheating and mitigation measures

Thank you

“To be able to look out of a sunlit window to see blue sky through the branches of a tree is one of life’s basic delights.

Sunlight lifts the mood, helps regulate the body clock, promoting quality sleep, it lowers blood pressure and

improves recovery rates in hospitals.

Yet too many people live and work in accommodation where natural light levels are poor, and where the sunlight is blocked by carelessly placed buildings.

An understanding of the different sources and qualities of natural light allied with

careful design can help to create a far happier, healthier habitat for people living in towns and cities.”

(UDG Robert Huxford, 2015)